Dr. Carpenter and his coworkers will be investigating substituent effects on the rates, regiochemistry and stereochemistry of a carefully selected set of pericyclic reactions. The specific projects currently in progress are: (1) A study of sbustituent effects on the rate of the aliphatic Claisen rearrangement. (2) Investigation of the effect of a potassium alkoxide substituent on the stereochemistry of a 1,3 sigmatropic migration. (3) A study of substituent effects on the rate and regiochemistry of 1,5 sigmatropic rearrangement in cyclopentadienes, This work is designed to test a theoretical model which, if verified, could provide the experimental organic chemist with the predictability necessary for the rational use of pericyclic reactions in syntheses of complex molecules, including molecules of pharmaceutical interest.